Two gay Manhattan hoteliers are profusely apologising for hosting an event for Republican presidential hopeful Ted Cruz after they were rattled by the threat of a boycott and a deluge of complaining emails, texts and phone calls.

"I was shaken to my bones" by the backlash, Ian Reisner, gay activist and co-owner of Out NYC Hotel, said on Facebook. "I made a terrible mistake. I was ignorant, naive and much too quick in accepting a request to co-host a dinner with Cruz at my home without taking the time to completely understand all of his positions on gay rights. I sincerely apologise for hurting the gay community and so many of our friends, family, allies, customers and employees."

The conservative Texas senator adamantly opposes gay marriage. He believes such a union should only occur between a man and a woman because it's "ordained by God".

Reisner's partner Mati Weiderpass also expressed his mea culpa. "The people that know me know the work that I have done over the last 20 years for the advancement of gay rights," he said in a separate posting. "Today, I came to realise that I might have nullified my past efforts and accomplishments in just one week."

Only about a dozen people attended the Cruz dinner and "fireside chat" earlier this month at the Midtown penthouse Reisner and Weiderpass own, the New York Times reported. Cruz discussed foreign policy and also said he believes the issue of gay marriage should be left up to the states. Cruz told listeners that he would "still love" his daughters, now 4 and 7, if they eventually came out as gay. "We love our daughter unconditionally," he explained.

It was a candid conversation

Reisner initially defended the event as a way to have a "candid conversation" with Cruz and perhaps sway his opinion on gay marriage. Reiser and Weiderpass do share Cruz's staunch support of Israel.

"My tireless support of the gay community and its causes worldwide has not and will not change; on the contrary I reaffirm my commitment to gay rights by not shying away from engaging with anyone opposed to us," Reisner said in a statement.

Reisner says he actually supports Hillary Clinton, and hosted a fundraiser for her months ago that drew some 900 people, reports the New York Daily News.

The market pressure on the hoteliers is an interesting twist on the new controversial religious freedom law in Indiana that emboldened businessmen not to serve customers who engage in behaviour, such as gay marriage, that they consider contrary to their religious beliefs. Cruz strongly supported the law. He criticised companies, such as Walmart, which opposed the measure, for serving a "radical gay agenda".